Trouble with 8Ft dish, notfinding any bird.

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nyfrench

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Dec 13, 2011
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<div class="bbWrapper">I setup a dish in my backyard, an 8 Ft parabolic from Sadoun with a DMX741 LNBF C/Ku. The receiver I have is a Junuo DVB-2500. There is only one problem, it does not hit anybird, none. Signal intensity is above 80s, however, the signal quality fluctuate between 0 and 1. The dish is rightly aligned. The satellites that came with the receiver are: Hotbird 13E, Nilesat 7E, Arabsat2B 33E, Badr 26E, Telstar 15E, Amos 4W, Sirius 4E8, Eutelsat W3A, Eutelsat W6, Turksat 1C, AsiaSat3S C 105. <br /> <br /> Also, there is no ability to add a satellite with polarity below 5150.</div>
 

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<div class="bbWrapper"><img src="/xen/smiles/welcome.gif" class="smilie" loading="lazy" alt=":welcome" title="Welcome :welcome" data-shortname=":welcome" /> to the forum, We&#039;re all her to help.<br /> Your latitude and longitude must be known before tuning a BUD on a polar mount. Along with active transponders on the satellite closest to your longitude<br /> The receiver must have active transponder frequency and SR programmed for the satellites you&#039;re going to use to aim and align the BUD. This may help - <a href="http://www.satelliteguys.us/c-band-satellite-discussion/222234-bud-manual.html" target="_blank" class="link link--internal" rel="noopener">http://www.satelliteguys.us/c-band-satellite-discussion/222234-bud-manual.html</a> <br /> Don&#039;t know anything about that model. If you&#039;re in N.A., hopefully you can change the satellite names, positions, and transponder info. <u><a href="http://thelist.satelliteguys.us/" target="_blank" class="link link--external link--favicon link--favicon--before" style="background-image:url('https://www.google.com/s2/favicons?domain=thelist.satelliteguys.us');" rel="nofollow ugc noopener">TheList</a></u> is a good resource for transponder info.</div>
 
<div class="bbWrapper"><blockquote data-attributes="" data-quote="nyfrench" data-source="post: 2740084" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/xen/goto/post?id=2740084" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2740084">nyfrench said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> I setup a dish in my backyard, an 8 Ft parabolic from Sadoun with a DMX741 LNBF C/Ku. The receiver I have is a Junuo DVB-2500. There is only one problem, it does not hit anybird, none. Signal intensity is above 80s, however, the signal quality fluctuate between 0 and 1. The dish is rightly aligned. The satellites that came with the receiver are: Hotbird 13E, Nilesat 7E, Arabsat2B 33E, Badr 26E, Telstar 15E, Amos 4W, Sirius 4E8, Eutelsat W3A, Eutelsat W6, Turksat 1C, AsiaSat3S C 105. <br /> <br /> Also, there is no ability to add a satellite with polarity below 5150. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> I have six foot polar mount dish from Sadoun and three DMX741&#039;s. Check that your f/D (focal length/Dish diameter) is set correctly. The f/D ratio for the eight foot dish is .385. Mine is .38. From the picture, the LNB seems too far away from the dish. The LNB has an f/D scale, with numbers 2,4,6,8,0,2. they represent f/D ratios of .2, .4, .6, .8, 1.0, 1.2. Set the LNB into the scalar ring so that the top edge of the scalar ring is aligned to .385. Your scalar ring may be different than mine. Check where the alignment reference is relative with the LNB.<br /> <br /> Easy to say; but, there are two problems.<br /> <br /> 1. The spacing between .2 and .4 is only about 7/32 inch. You have to guesstimate .385. You might do better with calipers or micrometer<br /> and pre mark the setting.<br /> 2. The set screw alignment is extremely crude. No chance for precision alignment. It really sucks.<img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f644.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":rolleyes:" title="Roll Eyes :rolleyes:" data-smilie="11"data-shortname=":rolleyes:" /><br /> <br /> However, If you are lucky you can get reasonable alignment.<br /> <br /> As I mentioned before I have three DMX741&#039;s. I thought they were all bad. I could not get any to work until found a way to preset the LNB&#039;s position.<br /> It would be very simple to use a spiral f/D pattern instead if the linear method. The numbers would be spaced further apart. Also mark the polarization angle scale around the middle part of the LNB rather than the impossible tic marks at the top.</div>
 
<div class="bbWrapper">robz,thanks for that info on the dmx741. i got mine adjusted about where you said, mine is at 4.2, but i had to fabricate my legs to attach the scalar ring to. charlie</div>
 
<div class="bbWrapper"><blockquote data-attributes="" data-quote="cyberham" data-source="post: 2740273" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/xen/goto/post?id=2740273" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2740273">cyberham said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Where are you located? Isn&#039;t elevation a little high? </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> I agree. A wood frame building with a peaked roof, a picket fence, and a winterized new aparment building in the background puts you north of 40 degrees latitude in North America. But your dish pitch puts you south of 40. Something does not fit Watson.</div>
 
<div class="bbWrapper">Since the picture shows a FEDDERS room air conditioner in top right corner, I am betting New Jersey Latitude... Watson said.</div>
 
<div class="bbWrapper"><blockquote data-attributes="" data-quote="T4Runner" data-source="post: 2740923" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/xen/goto/post?id=2740923" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2740923">T4Runner said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Since the picture shows a FEDDERS room air conditioner in top right corner, I am betting New Jersey Latitude... Watson said. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> And are those bars on all the windows, maybe a jail?</div>
 
<div class="bbWrapper"><blockquote data-attributes="" data-quote="sergei" data-source="post: 2740969" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/xen/goto/post?id=2740969" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2740969">sergei said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> And are those bars on all the windows, maybe a jail? </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> Only the difference between city living and the wide open spaces... ?</div>
 
<div class="bbWrapper">You are way way off track with the dish. Here is a chart to set the dish to track correctly. <a href="http://www.geo-orbit.org/sizepgs/decchartp.html" target="_blank" class="link link--external link--favicon link--favicon--before" style="background-image:url('https://www.google.com/s2/favicons?domain=www.geo-orbit.org');" rel="nofollow ugc noopener">Footprints by Dish Size - Latitude Declination Chart - C/Ku-Band Satellite Listing</a></div>
 
<div class="bbWrapper">This might me some help later on down the line. Granted it is dated, but it&#039;s still the same tricks used today as they were then.<br /> <br /> Never mind, that site is gone.</div>
 
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<div class="bbWrapper">Hello guys, thank you everyone for your prompt responses. I did not expect this much replies on such short notice, much appreciated. My longitude and latitude is 40.835524,-73.929757. I live in the Bronx, NY. <br /> <br /> Robz, I will dissect your info and readjust the LNB and take closer pictures for you guys to help me better. For receiver, I don&#039;t know how to go about that.</div>
 
<div class="bbWrapper"><blockquote data-attributes="" data-quote="T4Runner" data-source="post: 2740923" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/xen/goto/post?id=2740923" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2740923">T4Runner said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Since the picture shows a FEDDERS room air conditioner in top right corner, I am betting New Jersey Latitude... Watson said. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote> Well done Watson! Your observations and analytical skills are exemplary.</div>
 
<div class="bbWrapper">After following the wise counsels above, Please cover the centre hole. The dish does come with that cover. To my great surprise I found that it makes a great difference with the center cover on. My reasoning cannot explain that...may be someone here</div>
 
<div class="bbWrapper">i have a 6&#039; sadoun dish. i first tuned it up without the center hole covered because i couldn&#039;t figure out the circular plate and put it between the dish and the mount. then figured out it should have been a nice dish and moved it in front to cover the hole where the dish plates come together. well, nothing worked for reception so went through the tuning process again. it&#039;s working fine now and it works better with the plate installed correctly. charlie</div>
 
<div class="bbWrapper">If inserting the center hole cover improved the Signal Quailty readings, it is most likely that the LNB feedhorn is not properly centered and aimed at the center of the dish. Very suspect!<br /> <br /> The LNB assembly probably is off center and the dish aiming is compensating for this error by an increase or decrease in elevation and/or an azimuth adjustment.</div>
 
<div class="bbWrapper">I inserted few pictures of the LNB tuning. The first pic shows the dielectric plate. The last one shows the circular position at .385, roughly. The two in between show the LNB. I guess it&#039;s ready to be put back up again, with the 0 degree inscription placed in the middle, or place the sticker looking up. I&#039;m lost here.</div>
 

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<div class="bbWrapper">What satellites are you trying to receive that you&#039;re using the dielectric plate? There are only a few that require it.</div>
 
<div class="bbWrapper">The dielectric plate needs to be removed for all satellites over North America. Only needed on a few out over the Atlantic Ocean. Those that need it, the polarity will be labeled R or L. Those that don&#039;t need it , the polarity is labeled H or V. <a href="http://www.lyngsat.com/america.html" target="_blank" class="link link--external link--favicon link--favicon--before" style="background-image:url('https://www.google.com/s2/favicons?domain=www.lyngsat.com');" rel="nofollow ugc noopener">North &amp; South America - LyngSat</a><br /> Does your dish pivot with an actuator? How about some pictures of the backside of the dish, the mount (polar or Az-El), as that will determine how to aim it and the proper &quot;skew&quot; of the feed(741)<br /> Since it&#039;s a little known, or none, receiver you have, a few pics of the menu screens may help also. <br /> I think I remember the 741 requires the &quot;0&quot; to be placed along the vertical axis of the dish when used on a polar mount. see above about &quot;Skew&quot;. This is not the case if the dish is Az-El, unless you&#039;re only aiming at your zenith.</div>
 
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